In 1972, legendary standup comic George Carlin created the "seven words you can never say on television," a timeless routine beginning with the word "shit" and heading rapidly downhill. As a coach seeing hundreds of PowerPoints a year, I've evolved my own list of seven words startups should banish from every PPT they show, whether to prospective customers or prospective investors.

In short, my seven: Best, Disruptive, Innovative, Leading, Only, Unique, and (the worst of all) Cheapest. Here's why:

1. Best

Best is a lovely word, but it's a comparative: best compared to what, exactly, and judged by whom? Your team's or mother's love are great to have, but is hardly convincing, particularly when uttered by a startup.

Use "Best" only when the claim is backed by independent, credible data, as in "according to latest Consumer Reports ranking" or "Gartner says." Or perhaps "voted best by the Association of...." But these are seldom earned by new products.

The most famous exception here is likely Google, at launch: its dramatically different algorithm presented search results that were best for searchers, not advertisers. Thus Google quickly established "bestness," eclipsing 17 competing search engines.

2. Disruptive

Disruptive is the hot term du jour, among investors and consumers alike. But who exactly labels an innovation "disruptive?" Please send me their contact info.

Facebook clearly disrupted MySpace, the music-oriented social network. Acquired by NewsCorp for some $600-million in 2005, MySpace virtually evaporated as Facebook expanded from its .edu origins to today's 1.86 billion monthly users, clearly disrupting the social media marketplace. (To compare "disruptive" and "innovative," read on.)

3. Innovative

Innovative, similarly overused, cannot be a self-bestowed award. But when Inc., TechCrunch or Fortune call your product innovative, attribute the plaudit to a respected news source and gloat! Sometimes a product feature or feature set is truly innovative, as online financial service pioineers demonstrated some years ago.

Uber, for example, is hardly innovative. When it launched in San Francisco in 2011, similar digital ride-share competitors included RideCharge (later Taxi Magic, then Curb) founded in 2007, and brands Cabulous (later Flywheel) and GetTaxi (eventually Gett). Uber has nonetheless proven itself "disruptive." In New York City alone, some 250,000 passengers summon Ubers daily, approaching the number of street taxi hails per day.

4. Leading

Similarly, "leading" is a virtually worthless descriptor--a baseless claim that's meaningless for investors. Can an early-stage startup lead at anything? And like most words to avoid, it can be a turnoff to investors without third-party attribution.

What are you leading, anyway? An industry, category, or narrowly-defined market subsegment created to craft an otherwise baseless claim. How many "leading" recipe websites can there possibly be? Maybe yours is the "leading website for left handed chefs baking apple pies on weekends." Boo.

5-6. Only and Unique

Only and Unique are virtually synonymous. Use them with extreme caution, if ever. Global Entrepreneurship Monitor estimates that 17,000 business are started each day--in my opinion, an inflated number. How many--if any--are "one of a kind," unique businesses like Amazon.com or eBay or Google that dominate categories? Care to invest in "the only" discount retailer of left-handed pool cues in Nebraska?

7. Cheapest

I've saved my favorite for last: "cheapest." First, it's hardly a sustainable value proposition, since any serious competitor threatened by the claim can likely extinguish the fledgling opponent rather quickly by simply lowering prices, even for a little while. It's seldom defensible, for obvious reasons, and hardly much of a value proposition in many categories.

What to do?

Unsubstantiated claims, whether made to investors or customers, are often destructive--not positive--when it comes to encouraging funding a company or buying its products. And self-inflicted wounds from hyperbolic or unsubstantiated claims of greatness can do plenty of damage to those who make them.

Test your positioning repeatedly, face-to-face with the only people whose opinions matter--your potential customers. When your positioning starts to resonate consistently with folks in your target audience, perhaps at last you're on the road to explaining the value proposition your startup will deliver like none other.